Device for switching-off the feed of a coiled spring in a machine for the production of sprung structures



Nov. 20, 1962 pu L 3,064,693

DEVICE FOR SWITCHING- FF THE FEED OF A COILED SPRING IN A MACHINE FORTHE PRODUCTION OF SPRUNG STRUCTURES Filed Nov. 25, 1957 5 Sheets-Sheet lArr/3 Nov. 20, 1962 SPUHL 3,064,693

W. DEVICE FOR SWITCHING-OFF THE FEED OF A COILED SPRING IN A MACHINE FORTHE PRODUCTION OF SPRUNG STRUCTURES Filed Nov. 25, 1957 5 Sheets-Sheet 2//V VLF/V M41753? 5/ 0/94 {7 v IQMW @W M M Arry's.

Nov. 20, 1962 w. SPUHL 3,064,693 DEVICE FOR SWITCHING-OFF THE FEED OF ACOILED SPRING IN A MACHINE FOR THE PRODUCTION OF SPRUNG STRUCTURES 5Sheets-Sheet 3 Filed Nov. 25, 195'? 4; @6140 \Dm M M assess PatentedNov. 20, 1962 ice DEVICE FOR SWITCHING-OFF THE FEED A COILED SPRING IN AMACHKNE FUR THE PRO- DUQTIUN 0F SPRUNG STRUfITURES Walter Spiihl, 9Hompelistrasse, Sanlrt Gallon, Switzerland Filed Nov. 25, B357, 521'.No. 69%,dh5 Claims priority, application Germany Nov. 25, 1956 12Claims. (Cl. fi th-92.7)

The present invention relates to a device for switchingoff the feed of acoiled spring in a machine for the production of sprung structures suchas spring mattresses, for example.

For the better understanding of the invention it may be firstlydescribed briefly how in the usual manner cushion springs can beconnected in rows with one another by means of coiled springs:

FIGS. 1 and 2 of the accompanying drawings represent in quite adiagrammatic manner in elevation and plan view, respectively someessential components of a machine designed for that purpose, FIG. 2containing an electrical wiring diagram, which however will be referredto but later in connection with a preferred embodiment of the presentinvention.

The double-conical cushion springs 1 to be interconnected into a springmattress are arranged in pairs in parallel rows side by side, being heldin clamping tongs (not shown). T-wo spring wires 2 serve for connectingthe adjacent upper and lower end turns, respectively, of two adjacentcushion springs 1. For this purpose each wire 2 is engaged by a feederdevice 3, which in the usual way comprises two feeder-wheels or rollers(not shown), and is pushed thereby through a coiling or winding device4, wherein it is guided through a stationary curved groove so that it isshaped helically. The coiled spring 5 thus formed continuously grows inlength in the direction of the arrow 6 (FIG. 1) and screws itself in theprocess about the adjacent end turns of the cushion springs so that atany time two of these springs are connected with one another by thewindings of the coiled spring 5, and all pairs of cushion springs areconnected by the body of the coiled spring proper. When the coiledspring has reached the end position illustrated in PEG. 2, an eye isformed at its foremost turn by means of an eye-forming device 7. Thiseye is designed to prevent the coiled spring from unscrewing itself inthe course of time out of the turns of the cushion springs byinadvertent movements, and has moreover the purpose of preventing anydamage to covering fabrics, and any injuries.

Between the pair of cushion springs 1, which has been reached first bythe coiled spring 5, and the winding device 4, knives 8 are arranged, bymeans of which the coiled spring 5 is cut off after all the pairs ofsprings have been connected with one another by it. These knives arediagrammatically indicated in FIG. 2 only.

For the switching-off of the feeder device 3 in the known machines anelectric switch (not shown in FIGS. 1 and 2) is provided which isoperated by the free end 9 of the coiled spring 5, when the latter hasreached its end position shown in FIG. 2. With this arrangement howeverthe following difiiculties arise:

The feeder device 3 cannot interrupt the feeding processinstantaneously, namely not only because of the inertia of itsfeeder-wheels or rollers and of the advancing spring wire 2 or coiledspring 5, but also because of the inertia of the other members containedtherein e.g. of levers and clutches serving for the coupling of thefeeder-wheels or rollers to a continuously rotating shaft. Sinceconsequently some more spring wire is advanced after the coiled springhas reached its end position, a stress is set up in the coiled spring.When the coiled spring is then cut off by means of the knives 8, thecoiled spring expands again, whereby the formation of an eye at the rearend it) of the spring is rendered very diflicult. Since not always thesame wire material is worked with the machine and also the sluggishnessof the feeder device 3 is not quite constant but depends for example onthe lubrication, the expansion of the spring is not always the same, sothat it is very difficult to grip the extreme turn of the end if) of thewire safely with an eye forming device. One has therefore hithertodispensed with the forming of an eye at this end of the coiled spring orhad to put up with a rather complicated eye forming device. In somecases one has even to cut off a bit from the end 10 of the spring beforethe formation of the eye, in order to prevent the eye from lying too faroutside the spring assembly.

Moreover the difliculty arises that the end 11 of the coiled springprojecting from the winding device 4 does not in most cases remain trulyelastic after the cutting off but keeps a certain permanent deformation.The helical pitch and the diameter of the end 11 of the spring do nottherefore correspond accurately to their design dimensions any more,which leads into difficulties at the subsequent operation of themachine, in that this end of the spring does not screw itself correctlyinto the end turns of the cushion springs any more, or is not allowed topass at all by the tongs holding these cushion springs.

it is the main object of the present invention to provide a device forthe switching-off of the feed of a coiled spring wire in a machine forthe production of spring structures wherein cushion springs of the saidstructure to be connected with one another are arranged in pairs in twoparallel rows and the mutually contacting end turns of two adjacentcushion springs are connected with one another by means of the said coilspring wire passing through the same, in which the aforementioneddifiiculties are overcome. 7

It is another object of the present invention to provide a device of thekind referred to which is simple, rugged and reliable in operation.

With these and other objects, which will become apparent hereinafter, inview I provide a device of the kind referred to, comprising incombination: a feeder device advancing the said spring wire, an electricswitch arranged before the last pair of the said cushion springs in thepath of the said helically advancing coiled spring wire, an electricmotor in mechanical driving connection with the said feeder device andcontrolled by said switch, and control means adapted to adjust thesluggishness of the said feeder device in responding to theswitching-oif of the said motor by the advancing end of the said coiledspring wire actuating the said switch to such a magnitude that after theinitation of the said switchingoff operation the said coiled spring wirecomes to a standstill only after having passed through the said endturns of the said last pair of cushion springs.

In a preferred modification the feeder device for the spring wireserving for the production of the connecting coiled spring comprises aninertia device with an adjustable moment of inertia kinematicallycoupled to the said feeder device.

With reference to FIGS. 3 to 9 of the accompanying drawings threeembodiments of the device according to the present invention will now bedescribed by way of example:

FIG. 3 is a side elevation of a clamping tongs with a switch mountedthereon;

FIG. 4 is a plan view to FIG. 3;

FIG. 5 is a diagrammatic illustration of means for adjusting the timelag of the feeder device;

l clockwise direction.

re s? FIG. 6 diagrammatically shows another embodiment of theswitching-off device;

FIG. 7 is a diagrammatic illustration of a modified feeder device, and

FIGS. 8 and 9v are a side and an end elevation, respectively on aninertia device having an adjustable inertia moment.

In FIGS. 3 and 4, 12 is the body of a pair of tongs which serves for theclamping-in of the upper or lower end turns of the two last cushionsprings 1, i.e. of those on the extreme left of FIG. 2. This body 12 isin the usual manner mounted slidably on two supports 13 in order. thatthe distance between the pairs of cushion springs may be.varied. The.tongs have a fixed jaw 14 which is attached 'to the body 12 thereof bymeans of a countersunk screw 15. The moveable jaw 16 is slidable onguides 17 and is connected with an actuating bar 18. A .lever (notshown) pivotally mounted at 19,

which is operated pneumatically in the usual manner, bears on theprotruding end of the bar 18 so as .to bring the jaw 16 into the closingposition shown in the FIGS. 3 and 4 against the force of'a spring(likewise not shown). 7 7

On the body 12 of the tongs a, mounting plate 2% is fixed by means oftwo screws 21. On this mounting plate a switch 22 is fixed which in turncarries a small bearing, bracket. 23 for a switch lever 24, which .ispivotally mounted on a pin 25. A follower lever'26 is pivotally mountedon the same pin and is Connected to the 1ever.24 by a spring 27indicated diagrammatically. Opposite the. follower lever 26 theactuating button 23 of the switch 22 is arranged. The switch lever 24 isbiased in the anti-clockwise sense (FIG. 3) by a spring (not shown) sothat in the rest position it abuts at 29 a projection 30 of the fixedjaw 14.

The projection 30 has an inlet surface, 31 which is com'cally reducedtowards the jaw, and an adjoining semicylindrical surface .32, inv orderto guide the coiled spring in its advance in the sense of the arrow 33(see. FIG. 4) between the two jawsil4 and 16.- The upper end 34 of theswitch lever 24 has a bulge 35 which forms a carnbered ramp surface 36for the. coiled spring 5, which ramp surface of the bulge 35 has firstlya larger and then a smaller distance from the axis of the spring. Theprojection '30 is cut away at 38 toaccommodate the end turn of thecushion Spring 1 concerned.

' The jaws. 14 and 16. have at their insides in the usual manner such ashape that the end turns of both cushion springs 1 lie ouite closely toone another in the clamped position, without thereby preventing thecoiled spring from passing through the closed jaws when advancinghelically. V

When the end of the coiled spring advances from the. position of FIG. 4it comes into contact with the ramp surface 36 of the end of lever34 sothat. upon a further helical advance, the lever 24 is turned in theConsequently the follower lever 26hits the actuating knob of the switch22 which closes the circuit 39 (see FIG. 2), wherebv the 'switchins'ofioperation of'thje feeder device 3 is initiated. The sluggishness of thisdevice is so chosen that the feed stops only after the coiled spring 5'has passedalso throu h i the end turns of the two last cushion stations1, hich are contained in th fnnqs. FIGS. 3 and 4, 'whereafter it comestoa standstill in the end position accordin to FIG. 2. When the coiledspring 5 is then cut-off by the knives 8,the spring is stationary andits two ends and 11- are comnletelv free from stresses: no rebound ofthe end 10 takes place, and the end 11 shows the normal 'helical pitchand; normal diameter, whereby the difiiculties mentioned hereinab oveare overcome,

as the armature of an electro-magnet including an operat-' ing winding41. When this electro-magnet which is connected into the circuit 39, isenergised by closing the switch 22, the lever 40 is turned againstthe'bias of a spring 42, which is attached on the one hand to the lever40, and on the otherhand to a threaded bolt 43. On

the latter a wing nut 44 is fitted, by means of which the loading of thespring 42 can be adjusted in that the bolt is restrained from rotatingin any known way, e.g. by a stationary projection engaging alongitudinal groove of the bolt. The mechanical members of the feederdevice include a clutch operated by the said lever and are of well knowntype so that they do not need any further explanation (see US. PatentNo. 2,663,038 filed October 26, 1948, by Charles H. Gail, Los Angeles,California). It may be added, however, that when the lever 40 is, movedagainst the bias of the spring 42 that the clutch operated therebydisengages the feeder 3 from the wire 2 and that by adjusting theloading of the spring 4 2, the

moment at which the wire 2 stops advancing after the closing of theswitch 22 may be regulated with exactness.

The stronger the spring 42 is loaded the more. slug.- gishly reacts the,feeder device, i.e. the larger will bethe time lag between theexcitationof the electro-mag'net 41,

and the stand-still reached by the feeder-wheels or rollers. It has beenfound that in this manner the slug? gishness of the feeder device can beadjusted extremely accurately. to the value desired, so that theswitching-off device always functions faultlessly in the mannerdescribed, even npon changes of the material, diameter or helical pitchof the coiled wire (when exchanging the coiling device 4). i I

Accordingly it is also possible without difficulty to. provide the end10 of the coiled spring in a simple man: er with an eye. The ways andmeans how the eyes are formed at one and the other side are, however,not of importance to the present invention.

The feeder device described hereinabove, while inherently working verysatisfactorily, has yet some, disadvantages. In the first place itcannot be built up from normal commercially available components. In,particular the lever, electro-magnet and adjustable spring have to becombined into a special unit which in turn hasto be combined with aclutch. A further disadvantage consists m that comparatively involvedmeasures have .to be taken lest the clutch be immediately rerengagedwhen the i said switch opens as is the case in the. operational'cycle ofthe machine before the feeder'device may work again. These disadvantageshave been overcome by the em.-

bodiment according to FIG. 6. In this figure again'two ad acent cushionsprings l are connected toone another a by the coiled spring, 5, whichis produced in'the coiling device 4 and advances helically in thedirectionof the arrow 6. The spring wire 2. of which the coiled spring 5is formed is again pushed into the winding device 4 by a feeder device3.

The feeder device 3 comprises a motor 50, a feeder gear 51, a motorswitch 52 and a delayed action relay 53. The motor 5% is a conventionalthree-phase motor which maybe provided with a conventional brake-devicewhich becomes effective automatically when switching off the motor. Thefeeder gear 51 driven by themotor rollers for advancing the spring wire2.

59 comprises in the 'usual'manner feeder-wheels or and a bi-metaloverload contact 57. The switch arms 54 are connected to the three-phasemains. The delayed action relay 53 comprises an input impedance 59formed e.g. by a rectifier, an adjustment lever 60 and a contact 61; itstime lag is adjustable in the known manner, e.g. by adjusting a resistorthrough which a condenser is charged the voltage of which controls theigniting of a thyratron valve in series with a magnet coil. (A relay ofthis type is the REZ 1-4 relay of Sprecher und Schuh, Aarau.)

The input impedance 59 is connected in series with a switch 22, which isclosed by the spring 5 advancing helically, to a source of controlvoltage 62. In another circuit connected to this source 62 there is arelay contact 61, a switch 63, the said switch coil 55 and the bi-metalcontact 57. The switch 63 is operated by a cam 64 mounted on a controlshaft 65 which may be turned by means of a hand wheel 66. On the saidcontrol shaft 65 there are also further cams (not shown) which serve forthe control of other operational motions of the machine when the handwheel is turned. A circuit breaker contact 67 is connected in serieswith the holding contact 5s.

The switching-off device described is shown in the drawing in thatswitching condition which prevails at the moment preceding the abuttingof the end of the coiled spring on the still open switch 22. The switcharms 54 are closed since the switch coil 55 is excited by the controlcurrent source 62 on the one hand over the bimetal contact 57 and on theother hand over the holder contact 56, the circuit breaker contact 67and the relay contact 61. The motor 58 is accordingly in operation andeffects the advance of the spring wire 2 by means of the feeder gear 51.

As soon as the end of the coiled spring 5 has closed the switch 22 inthe manner described in more detail hereinabove, the input impedance 59is energised, which after the time lag adjusted to, entails an openingof the contact 61. The switch coil 55 is accordingly de-energised, theswitch arms 54 are opened by a spring (not shown), and the motor St) isbrought to a standstill. During the time lag of the relay 53 and duringthe running-out time of the motor 50 and the gearing 51 the coiledspring 5 keeps advancing screw-wise, and thereby passes also through themutually contacting end turns of the last two cushion springs 1, asindicated in the drawing in chain-dotted lines. The sluggishness of thefeeder device 3, which depends mainly on the delayed action of the relay53, the inertia and friction of the motor 5i; and of the gearing 51, maybe adjusted by controlling the time lag of the relay easily in such amanner that the coiled spring after actuating the switch 22 keepsadvancing a stretch of predetermined length.

The motor 56 then keeps at a standstill until the cam 64- closes theswitch 63 upon turning the hand wheel 66. Since in the meantime theinterconnected cushion springs have been removed from the tongs in whichthey were clamped during the operation described, and since consequentlythe switch 22. has been opened again, the input impedance 5? had beende-energised in the meantime which caused the relay contact 61 to beclosed. When closing the switch 63, accordingly the switch coil 55 isenergised again which involves the closing of the switch arms 54 and ofthe holding contact 56. The motor 59 accordingly drives again the feedergear 51, and two new rows of cushion springs 1 are connected with oneanother by a new coiled spring 5.

By means of the circuit breaker contact 67 the circuit of the switchcoil 55 can be interrupted in case for one reason or another, e.g. upona breakdown of the switch 22 or of the relay 53, it is desired to bringthe motor 58 to a standstill outside the normal operational cycle. Thebi-metal contact 57 heats up in the case of excessive current in thewindings of the motor, and then disconnects the switch coil 55 from thesource of exciter current 62, so that the motor is brought to astandstill.

The advantage of this second embodiment as compared with the embodimentdescribed first, consists in that the motor switch and the delayedaction relay of the kind described are readily obtainable. Since a motorswitch has to be provided anyway and moreover a disengageable clutch isdispensed with, the feeder device 3 becomes particularly simple andinexpensive. Moreover the restarting of the motor at the right moment ofthe working cycle is effected in a very simple manner. Obviously thedelayed action relay need not be necessarily of the thyratron type.

Referring now to FIGS. 7 to 9, a modified feeder device is illustratedin FIG. 7. It comprises a direct currentor alternating current-motor 70,which is supplied from the mains terminals 71 through a relay switch 72which is opened as soon as the circuit 39 is closed by the switch 22. Onthe shaft 73 of the motor 70 an inertia device 74 with adjustableinertial moment and a driving pulley 75 are attached which through anendless driving member 76, e.g. a chain or a belt, and a driving pulley77 drives a feeder gearing 77. The feeder gearing comprises in the usualway feeder rollers, which advance the Wire 2 clamped between them.

FIGS. 8 and 9 show the structural design of the inertia device 74-. Thesame has a block 78 bored through, which is provided with a hub 7? andmounted on the shaft 73 to which it is connected by means of a pin Sii.The block 73 has two parallel bores 31 and 82 in which round rods 33 andS4- are inserted serving for the guiding of counterpoises 85 and asholding one another in equiiibrium, and secured in their position byclamping screws 87 and 83. The rod 84 is provided with opposite screwthreads 89 and 99 which are screwed into correspending tapped bores ofthe counterpoises 85 and 86. Moreover 'on both sides of the block 78 twoadjustable collars 9i and 92 are mounted on the rod 84. On the ends ofthe screw threads 3? and 9t) nuts 93 and W, respectively, are screwed.

it is clear that by turning the preferably knurled adjustable collars 9iand 92 the rod 84 can be turned and thereby the distance of thecounterpoises 85 and 86 from the shaft 73 can be varied in the oppositedirection, the counterpoises sliding on the rod 33 and being restrainedby the nuts 93 from moving away too far.

By adjusting the inertia device 74 the deceleration rate and stoppingperiod of the motor 70 and of the feeder gearing 77 driven by it can beadjusted in a very precise manner, it being apparent that thecounterpoises 85 and 36 act in the manner of a flywheel and when movedapart will cause the shaft 73 to rotate (due to the pressure of suchcounterpoises) for a longer period than when they are moved to aposition nearer to each other. This stopping period is so regulated thatthe coiled spring 5 continues advancing after the actuation of theswitch 22 until its free end comes into the end position shown in FIG.2, in which it can be engaged by the eye-forming device.

The switching-off device described with reference to FlOS. 7 to 9 ismechanically extremely rugged and very reliable in operation, since itdoes not comprise any sensitive components liable to break-downs.

While I have herein described and in the accompanying drawings haveillustrated what may be considered typical and particularly usefulembodiments of my said inventron, i wish it to be understood that I donot limit myself to the particular details and dimensions described andillustrated, for obvious modifications will occur to a person skilled inthe art.

What I claim as my invention and desire to secure by Letters Patent, is:

l. A device for automatically switching-off the feed of a coiled springwire in a machine for the production of sprung structures whereincushion springs of the said .7 structure to be connected with oneanother are arranged in pairs in two parallel rows and the mutuallycontact ing end turns of two adjacent cushion springs are connected withone another by means of the said coiled spring wire passing through thesame, comprising in combination: a feeder device helically advancing thesaid spring wire, an electric switch arranged in the path of the saidcoiled .spring wire before the last pair of the said cushion springs, anelectric motor in mechanical driving connection with the said feederdevice and in electrical wiring connection with the said switch, andcontrol means including an inertia device having an adjustable moment ofinertia operable by the advancing end of said wire into contact withsaid switch to open the latter to adjust the sluggishness of the saidfeeder device in responding to the switching-E of the said motor to suchextent that after the opening of said switch the said coiled spring wirecomes to a standstill only after having passed through the said endturns of the said last pair of cushion springs.

' 2. A device as claimed in claim 1 comprising a pair of tongs having afixed jaw and a moveable jaw, between themselves clamping the said endturns, the said switch being attached to the said 'fixed jaw.

3. A device as claimed in claim 2, comprising a projection of the saidfixed jaw guiding the said coiled spring wire, a switch lever pivoted onthe said switch and provided with a cambered ramp surface to becontacted by the advancing end of the said coiled spring wire, the saidlever being spring-biased against the said projection in the restposition, and turned in the sense of actuating said switch by the saidadvancing end of the coiled spring wire.

4. A device as claimed in claim 3, comprising a follower lever pivotedfreely relative to the said switch lever, a spring spacing the saidfollower lever resiliently from the said switch lever, and an actuatingbutton provided on the said switch in operative relation to the saidfollower lever, the said switch lever when contacted by theiadvancing'end of the said coiled spring wire transmitting its movementto the said follower lever through the said spring.

5. A device as claimed in claim 3, comprising an electro-magnetelectrically connected to the said switch, an armature spring-biased inopposition to the attraction of the saidelectro-magnet, and adjustmentmeans adapted to vary to strength of this spring biased opposition, thesaid armature forming an actuating lever operatively connected with andadapted to arrest the said feeder device.

6. A device for automatically switching-0E the feed of a coiled springwire in a machine for the production ofsprung structures wherein cushionsprings of the said; structure to be connected with one another arearranged in pairs'in two parallel rows and the mutually I contacting endturns of two adjacent cushion springs are connected with one another bymeans of the said coiled'spring wire passing through the same,comprising in combination: a feeder device advancing the said springwire, an electric switch arranged before the last pair of said cushionsprings in the path of the said coiled spring wire advancing screw-wise,an electric motor in mechanical driving connection with the said feederdevice and in electrical wiring connection with the said switch, adelayed action relay with adjustable time lag electrically connectedbetween the said switch and the said motor, the said relay being adaptedto adjust the bination: a motor switch having switch arms controllingthe electrical connection of the said motor to the mains and springbiased: towards the opening position, a switch coil elcctro magneticallymoving when ener-- gised the said arms towards the closing position, .asource of a control voltage adapted to be electrically connected to thesaid switch coil, a contact of the said delayed action relay controllingthe electrical connection of the said source to the said switch coil andan input im-. pedance of the said relay electrically connected to thesaid switch actuated by the said advancing end ofthe coiled spring wirethe said input impedance being energised upon actuation of the saidswitch in the sense of de-energising said switch coil and therebyopening the said switch arms.

8. A device, for automatically switching-0E the feed of a coiled springwire in a machine for the production of sprung structures whereincushion springs of the. said structure to be connected withone anotherare arranged in pairs in two parallel rows and the mutually contactingend turns of two adjacent cushion springslare connected with one anotherby means of the. said coiled spring wire,- passing through the same,comprising in combination: a

feeder device advancing the said spring wire, an electric end switcharranged in the path of'the saidspring wire 7 advancing helically beforethe last pair of the said cushion ing the said end switch to such a'magnitude that after the initiation of-the said switching-elf operationthe said coiled spring wire comes to a standstill only after havingpassed through the said end turns of the'said last pair of cushionsprings.

9. A device as claimed in claim 8, wherein the said inertia device ismounted on the output shaft of the said electric motor.

10. A device as claimed in claim 8, comprising a relay.

switch in electrical wiring connection both with the said electric endswitch and with the said electric motor, the

said relay switch being energised by the closing of the said end switchand when energised switching off the current supply to the said electricmotor. p

11. A device for automatically switching-0E the feed of a coiled springwire in a machine for the production of sprung structures whereincushion springs of the said structure to be connected with one anotherare arranged in pairs in two parallel rows and the mutually contactingend turns of two adjacent cushion springs are connected with one anotherby means of the said coiled spring wire passing through the same,comprising in combination;

a feeder device advancing the, said spring wire, an electric end switcharranged in the path of the said spring wire advancing helically beforethe last pair of the said cushion springs, an electric motor having anoutput shaft in mechanical driving connectionwith the said feeder deviceand in electrical wiring connection with the said end switch, andaninertia device having an adjustable inertia moment,

kinematically connected to the said feeder device and adapted to adjustthe sluggishness of'the' said feeder de-- vice in responding totheswitching-ofi of the'said motor by the advancing end of the said coiledspring wire actuating thesaid end switch to such amagnitude that afterthe initiation of the said switching-off operation the said coiledspring wire comes toa standstill only after having passed through thesaid end turns, of the said last pair of cushion springs, said inertiadevice comprising .a rod having opposite screw threads at its two endsand mounted transversely of the said output shaft on the same rotatablyabout its own axis, and two counter-poises each in screwconnection withone end of the said rod and restrained from rotating about the axisthereof, the said two counterpoises being adjustable in oppositedirections relative to the said output shaft by turning the said rod, insuch a manner as holding one another always in equilibrium.

12. A device for automatically switching-off the feed of a coiled springwire in a machine for the production of sprung structures whereincushion springs of the said structure to be connected with one anotherare arranged in pairs in two parallel rows and the mutually contactingend turns of two adjacent cushion springs are connected with one anotherby means of the said coiled spring wire passing through the same,comprising in combination: a feeder device advancing the said springwire, an electric end switch arranged in the path of the said springwire advancing helically before the last pair of the said cushionsprings, an electric motor having an output shaft in mechanical drivingconnection with the said feeder device and in electrical wiringconnection with the said end switch, and an inertia device having anadjustable inertia moment, kinematically connected to the said feederdevice and adapted to adjust the sluggishness of the said feeder devicein responding to the switching-oh of the said motor by the advancing endof the said coiled spring wire actuating the said end switch to such amagnitude that after the initiation of the said switching-off operationthe said coiled spring wire comes to a standstill only after havingpassed through the said end turns of the said last pair of cushionsprings, said inertia device comprising a block fixedly mounted on theoutput shaft of the said electric motor, a rod oppositely screw-threadedat both ends rotatably fitted into the said block transversely of thesaid output shaft, a guide rod fitted into the said block parallel tothe said screw-threaded rod, two counterpoises each with a screw-tappedbore in screw-engagement with one end of the said screw-threaded rod,and a smooth bore in sliding fit over the said guide rod, the distanceof the said counterpoises from the said output shaft being variable bytuming the said screw threaded rod, and arrester means adapted torestrain the said screw-threaded rod from rotating.

References Cited in the file of this patent UNITED STATES PATENTS1,812,122 Streine June 30, 1931 1,814,890 Biagosch July 14, 19312,172,483 Taylor Sept. 12, 1939 2,262,994 Dickey Nov. 18, 1941 2,470,812Gauci et al. May 24, 1949 2,548,542 Macgeorge Apr. 10, 1951 2,649,120November Aug. 18, 1953 2,663,038 Gail Dec. 22, 1953 2,694,418 BergstromNov. 16, 1954

